Relating to sphygmometers

Abstract

A cuff member for a sphygmomanometer that has a manually rotatable spindle mounted in a housing. One end of an inflatable cuff is attached to and wound spirally on the spindle. The spiral-wound portion of the cuff in use remaining at least partially inflatable but provides the effect of a constriction at a position along its length dependent on the extent of the spiral wound portion. The inflatable cuff extends through an opening in the housing. An end unit is attached to the other end of the inflatable cuff. A releasable fastening member fastens the end unit to the housing. A desired effective length of cuff is withdrawn from the housing via the opening to extend in a loop around the upper arm of a patient. A ratchet cooperates with the spindle to allow withdrawal of the cuff from the housing when the spindle is manually rotated in one direction and to restrain withdrawal of the cuff from the housing for rotation of the spindle in the opposite direction.

What is claimed is:  
     
       1. A cuff member for a sphygmomanometer comprising a housing, a spindle manually rotatable therein, and an inflatable cuff having one end attached to said spindle and being wound spirally on said spindle, the spiral-wound portion of the cuff in use remaining at least partially inflatable but providing the effect of a constriction at a position along its length dependent on the extent of the spiral wound portion, a length susceptible to inflation, the inflatable cuff extending through an opening in the housing, an end unit attached to the other end of the inflatable cuff, a releasable fastening member for releasably fastening said end unit to the housing when a desired effective length of cuff has been withdrawn from the housing via said opening to extend in a loop around the upper arm of a patient, and a ratchet mechanism mounted in cooperation with the spindle to allow withdrawal of the cuff from the housing when the spindle is manually rotated in one direction and restrain withdrawal of the cuff from the housing for rotation of the spindle in the opposite direction. 
     
     
       2. Cuff member according to  claim 1 , characterized by the cuff, in use, adopting a frusto-conical form to accommodate the taper of a subject's limb. 
     
     
       3. Cuff member according to  claim 1  characterized in that the opening is provided by a slot formed between two cooperating parts of the housing. 
     
     
       4. Cuff member according to  claim 1 , characterized in that the releasable fastening member comprises mutually co-operable snap-fastening attachments provided on respectively the end unit and the housing. 
     
     
       5. Cuff member according to  claim 1 , characterized in that the releasable fastening member is attached to one of the end unit and the housing in a manner permitting relative twisting between said end unit and said housing. 
     
     
       6. Cuff member according to  claim 5 , wherein the degree of permitted twisting is in the range 5° to 15°. 
     
     
       7. Cuff member according to  claim 6 , wherein the releasable fastening member is attached to one of the end unit and the housing in a manner permitting their relative twisting such that the taper of a subject's limb is automatically accommodated in use by the permitted relative twisting permitted by said releasable fastening. 
     
     
       8. Cuff member according to  claim 1 , characterized by said ratchet mechanism being one-hand operable and comprises a rotatable input member and a rotatable output member, rotation of the input member in a first direction effecting rotation of the output member in that direction but preventing rotation of the output member in a second, opposite direction, and rotation of the input member in the opposite second direction permitting rotation of the output member in that second direction. 
     
     
       9. Cuff member according to  claim 8 , characterized in that said rotatable input member is a knob unit and the rotatable output member is constituted by said spindle, the knob and spindle being coaxial with one another. 
     
     
       10. Cuff member according to  claim 8 , characterized by first and second mutually engageable ratchets that, when the input member is rotated manually in said first direction, are in mutual co-operative engagement to prevent said rotation of the output member in the second direction, and that are disengaged when the input member is rotated manually in the said opposite, second direction to enable said rotation of the output member in the second direction by the same one-handed operation. 
     
     
       11. A cuff member for a sphygmomanometer comprising a housing having a wall provided with an elongate opening, a spindle rotatable therein, and a cuff inflatable throughout its length, wherein the inflatable cuff extends through said opening, has one end attached to said spindle and is wound spirally on said spindle, the spiral-wound portion of the cuff in use remaining at least partially inflatable but restrained against expansion at a position along said length dependent on the extent of the spiral wound portion, whereby the said length can be manually varied from a maximum to an effective length extending away from the spindle and less than the maximum further characterized by a one hand operable ratchet mechanism to restrain withdrawal of the cuff from the housing, and a release operable to permit such withdrawal, said ratchet mechanism comprising a rotatable input member including a knob unit and a rotatable output member co-axial with the knob and constituted by said spindle, rotation of the input member in a first direction effecting rotation of the output member in that direction but preventing rotation of the output member in a second, opposite direction, and rotation of the input member in the opposite second direction permitting rotation of the output memeber in that second direction.